Refrigerating apparatus



May 14, 1935.

H. J. DICK REFRIGERATING APPARATUS Filed April 29. 1931 g il ii Illll mIlll Ii Illllll nih iiugggmm 2 Sh'eetsSheet l E -INVEIE(3R Q M ATTORNEYMay 34, 1935.

H. J. DICK REFRIIGERATIEG APPARATUS Filed April 29, 19:51

2 Sheets-Sheet 2 Ill ATTORNEY Patented May 14, 1935 UNITED STATES PATENTOFFICE 2,001,323 REFRIGERATING mm'rus Application April 29, 1931, SerialNo. 533,739

9 Claims.

This invention relates to refrigerating apparatus 'ofthe type whichincludes a'cooling element adapted to be placed in the path of a coolingmedium; and which is adapted to be maintained normally at a temperaturecausing solidification of a part of such 1 medium flowing thereover andmore particularly to improved means for quickly removing the solidifiedmedium accumulated on said cooling element.

One of the objects of this invention is to provide improved means forfreeing the cooling element from frost and ice accumulated thereon.

More specifically it is an object to provide an artificial heatingelement within the confines of the cooling element for applying its heatto the refrigerant in the cooling element so as to cause melting of theice or frost on the walls of the cooling element to thereby quicklyremove the frost and ice from the cooling element.

Further objects and advantages of the present invention will be apparentfrom the following descriptiomreference being had to the accompanyingdrawings wherein a preferred form of the present invention are clearlyshown.

In the drawings;

Fig. 1 isadiagrammatic illustration of a refrigerating system embodyingfeatures of the invention;

Fig. 2 is a diagrammatic illustration of a modified form ofrefrigerating system embodying features of the invention.

Fig. 3 is a top plan view of a cooling element embodying features of theinvention;

Fig. 4 is a front view of a cooling element em-- 35 bodying myinvention; and t Fig. 5 is a side view of the cooling element shown inFig. 4 and showing a portion thereof in elevation and a portion in crosssection.

In refrigerating rooms, compartments, cab- 40 inets and the like it isusual to place a cooling element such as an evaporator in the space tobe cooled and to circulate refrigerant through the cooling element bymeans of a refrigerant circulating element which usually operates auto-45 matically in response to normal conditions within the system to chillthe cooling element and induce circulation of air in the space to becooled. The cooling element soon becomes coated with frost and iceformed by the freezing water con- 50 densing on the cooling element fromthe circulating air and this frost and ice forms a resistance to thetransfer of heat from the air to the cooling element and thus reducesthe efiiciency of the system. Since the refrigerating requirements of 55the space vary from time to time and since refrigeration is produced bythe apparatus at a fairly uniform rate, which rate must be slightlyhigher than the maximum requirement of the space to be cooled, it isusual to operate the refrigerating system intermittently in order toprevent cooling the space below the desired temperature.

In practicing this invention it is a further object to prevent operationof the refrigerant circulating element in response to normal conditionswithin the system when it is desired to defrost the cooling element.This is preferably accomplished by providing means for rendering therefrigerant circulating element inefiective to operate in response tonormal conditions within the system and simultaneously rendering thedefrosting device operative to free the cooling element of frost andice. I have also arranged for the automatic restoration of said means toits normal position in the event certain abnormal conditions occurwithin the system to thus render the defrosting means ineffective toproduce its function and to place the refrigerant circulating element inreadiness for operation.

Referring to the drawings, and particularly to Fig. 1, 20 designates thecooling element for cooling the compartment 2|, the cooling elementbeing shown for the purpose of illustration as including headers 24 and25 forming reservoirs for liquid refrigerant, the level of which I haveindicated at 21. This level is maintained substantially constant by afloat valve not shown herein but fully described in the patent to Osborn1,556,708, October 13, 1925. In the specific embodiment, the coolingelement also includes a plurality of conduits communicating with bothheaders, and thermal conducting fins 32 in contact with the conduits.

Liquid refrigerant is supplied to the cooling element by a liquidconduit 35 and the evaporated refrigerant is withdrawn from the coolingelement through a vapor conduit 31, both conduits being suitablyconnected to a refrigerant circulating element 40. The element includesa condenser 42, a receiver 43 to which the conduit 35 is connected, acompressor 45 and a motor 41 for driving the compressor. The motor issupplied with current through the power mains 48 under the control of anautomatic switch 50-. The switch 50 is actuated in response to normalconditions within the system for starting and stopping the motor, andfor instance, in response to change in pressure of refrigerant withinthe cooling element and in the vapor conduit 31 which change in pressurecorresponds uniformly with changes in temperature of the cooling elementand refrigerant contained therein. The switch includes an expansiblebellows-52 and suitable leverage mecha-.

nism 53 pivoted at 54.

In many instances the cooling element 28 is employed to maintain frozenfood articles in their frozen condition and consequently to maintain thetemperature of the storage or display compartment in which they arestored below the thawing point of such articles. For this reason it isdesirable to quickly defrost the cooling element so as to prevent thetemperature in said compartment from rising above the thawing point ofsaid articles. Thus it is desirable to rapidly defrost the coolingelement.

In accordance with this invention I provide means for quickly defrostingthe cooling element.

This means comprises an electric heating element' 68. In order torapidly defrost the cooling element I have placed this electric heatingelement within the confines of the cooling element and have arranged forapplying its heat directly to the refrigerant in the cooling elementbefore apply- .ing the heat to the walls of the cooling element. In suchinstance it is obvious that the connection of the heating element at thepoint where it passes through a wall of the cooling element must beinsulated. As shown in Fig. 1 the portion of the heating elementextending into the cooling element is preferably spaced from wallsthereof and is immersed in the liquid refrigerant in the element 28. Inthis embodiment the heating element passes through the lowermost conduit38 and extends into both headers 24 and 25 below the level of liquidrefrigerant therein. Thus it will be apparent that the heating elementgives up its heat directly to the refrigerant which causes it to boiland circulate warm refrigerant throughout the entire cooling element.The temperature of the walls of the cooling element will be increased bythe heated refrigerant causing the ice and frost to melt loose from thewalls and drop from the cooling element in large chunks.

The circuit throughout the heating element is completed upon closure ofa set of contacts 65 which takes place in a manner about to bedescribed.

During defrosting periods of the cooling element it is desired to renderthe refrigerant circulating element inoperative and in order toaccomplish this I have provided a suitable arrangement which renders theswitch 58 ineffective to normal conditions within the system for causingoperation of the circulating element while at the same time the circuitthrough the electric heating element is completed. I have provided apivoted lever I8 which moves the leverage mechanism 53 upwardly toengage the movable member of the contacts 65 to close the electricheating circuit and by this upward movement of the leverage mechanismthe switch is moved out of its normal operating position and isineffective to normal pressures in the bellows 52. In order to maintainthe heating circuit closed and to maintain the leverage mechanism 53 outof its operating position I have provided a resilient locking device 15which receives the handle end I6 of lever -I8. This locking device keepsthe lever 18 locked in position during the defrosting period andprevents the downward movement of the leverage mechanism during thedefrosting operation. However, if the user of the apparatus shouldforget to actuate the lever I8 after the cooling element has beendefrosted to thus return the leverage mechanism 53 to its position whereit is in condition to control operation of the circulating element, andto interrupt the heating circuit, the lever I8 will be automaticallyactuated in response to abnormal conditions, such as extreme pressurescreated under the influence of the heating element within ,the coolingand conduit 31 by means of the bellows 52 which at that time moves theleverage mechanism to separate the lever I8 from its resilient lockingdevice 18 and also interrupts the heating circuit by causing the movablemember of contacts 65 to be separated from the stationary member of saidcontacts. The pressure at which the bellows 52 renders the defrostingdevice inefl'ective and restores switch 58 to normal operating positionoccurs after the cooling element has been entirely defrosted.

Fig. 3 shows a cooling element 88 similar in all respects to the coolingelement 28 and this cooling element comprises in general a pair ofheaders 8| and 82, interconnecting conduits and fins 86 all of whichcorrespond to similar parts of the cooling element 28. In this viewthere is shown a heating element 81 and a second heating element 88located at opposite ends of the cooling element. In some instances ithas been found on large cooling elements that the two heating elementswere desirable to more quickly remove the frost and ice from the coolingelement. The heating elements 81 and 88, corresponding to the heatingelement 68, are positioned within the heating element in the same manneras the element 68 is positioned in the cooling element 28 and the mannerof operation of said heating elements 8! and 88 is the'same as themanner of operation of heating element 68, and if desired these twoheating elements 81 and 88 may be connected in series and controlled bya single set of contacts in the same manner as heating element 68.

Referring now to Fig. 2 there is shown a modified form of refrigeratingsystem commonly known as a dry expansion system. In this modification Ihave shown a cooling element or expansion coil I88, and a refrigerantcirculating element I82. The refrigerant circulating element I82supplies liquid refrigerant to the cooling element I88 through conduitI84 under the control of an expansion valve I85. Evaporated refrigerantis returned to the circulating element throughavapor conduit I81.Refrigerant circulating element I82 correspondsin all respectstorefrigerant circulating element 48 showninFig.1. Thus the refrigerantand its circulating element includes condenser II8, compressor III andmotor II4 which drives the compressor. The motor is supplied withcurrent through power mains H5 and is controlled in response to thetemperature bf the cooling element I88 by means of an automatic switch I28. The switch I28 includes an expansible bellows I2l actuated by meansof a thermostatic bulb I22 which in this illustration is shown incontact with the last coil of the cooling element I88. In thisparticular embodiment refrigerant in the cooling element I 88 during theoff cycle of the system will collect in the lowermost portion of saidcooling element at which place I have provided a reservoir I25 forliquid refrigerant.

In the reservoir I 25 I have disposed an electric heating element I21which corresponds to the heating element 88 and is controlled in asimilar manner as the heating element 68 is controlled. Thus theautomatic switch I28 may be employed for cyclically operating therefrigerant circulating element I02 and by means of a leverage mechanismIII the automatic switch I2. is rendered ineffective to normalconditions within the system to thus prevent operation of the system andalso by the leverage mechanism III the heating circuit through theelectric heating element is closed for heating the refrigerant withinthe cooling element I00 to thus rapidly defrost the cool-' ing elementI00. The leverage mechanism I is arranged in a similar manner as theleverage mechanism I0 shown in Fig. 1 and in the event of abnormalconditions within the system such as for instance extremely hightemperature within the cooling element I00 created under the influencesof the heating element located within the cooling element I00 to thuscause the thermostatic bulb I22 to expand bellows I2I sufficiently toreturn the switch I20 to its normal operating position and to interruptthe circuit through the electric heating element in a similar manner asthe device described in Fig. 1.

Figs. 4 and 5 show views of a modified form of cooling element embodyingfeatures of the present invention. In these figures there is disclosed acooling element or evaporator I50 which is of the flooded, floatcontrolled type having fioat valve mechanism similar to the typedisclosed in the patent to Osborn 1,556,708, issued October 13, 1925.Evaporator I50 comprises in general a header I53 adapted to provide areservoir for liquid refrigerant and a plurality of depending ducts I55for circulating the liquid refrigerant. At the lowermost portion of thecooling element I50 there is provided a liquid refrigerant manifold I51which communicates with each of the depending ducts I55. In thismanifold I51 I- have disposed an electric heating element I50 forrapidly removing frost and ice from the cooling element I50 in themanner hereinbefore described. Thus it will be noted that the heatingelement I50 is immersed in the liquid refrigerant and applies its heatdirectly to the refrigerant within the cooling element for defrostingthe element. The heating element and the control of the supply of liquidto the element I50 may be accomplished in the same manner as describedwith reference to Fig. 1.-

While the forms of embodiments of the invention as herein disclosed,constitute preferred forms, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. An intermittently operated refrigerating system comprising incombination a cooling element, a refrigerant circulating element adaptedto supply refrigerant to said cooling element, said cooling elementbeing maintained normally below a predetermined temperature range, meansresponsive to normal conditions within said system for controlling theoperation of said refrigerant circulating element, an artificial heatingelement located within the walls of said cooling element and arranged toapply its heat directly to refrigerant in the cooling element fordefrosting said cooling element, and means for simultaneously renderingsaid heating element effective and for rendering said first named meansinefiective to normal conditions within said system.

2. An intermittently operated refrigerating system comprising incombination a cooling element, a refrigerant circulating element adaptedto supply refrigerant to. said cooling element, said cooling elementbeing maintained normally below a predetermined temperature range, meansresponsive to normal conditions within said system for controlling theoperation of said refrigerant circulating element, artificial heatingelement located within the walls of said cooling element and arranged toapply its heat directly to refrigerant in the cool'ng element fordefrosting said cooling element, and means for rendering said heatingelement effective and for rendering said first named means ineffectiveto normal conditions within said system. and said first named meansbeing responsive to abnormal conditions within said system for renderingsaid heating element lneifective and for automatically restoring itselfin normal operating position.

3. Refrigerating apparatus comprising in combination a cooling elementadapted to contain a quantity of liquid refrigerant and upon which frostand ice accumulate, an electric heating element enclosed within walls ofthe enclosure formed by said cooling element and disposed in directcontact with refrigerant therein, and means actuated automatically inresponse to conditions of sad refrigerating apparatus for controllingthe electric circuit of said heating element.

4. Refrigerating apparatus comprising in comination a cooling elementadapted to contain a quantity of liquid refrigerant and upon which frostand ice accumulate, an electric heating element enclosed within walls ofthe enclosure formed by said cooling element and disposed in directcontact with refrigerant therein, and means actuated automatically inresponse to pressures of refrigerant within said refrigerating apparatusfor controlling the electric circuit of said heating element.

5. The method of defrosting a cooling element of a refrigerating systemcontaining a quantity of refrigerant which consists in, causing heatgenerated by an electrical heating element to be applied inside thewalls of the cooling element and directly to refrigerant containedtherein automatically in response to conditions of the refrigeratingsystem.

6. The method of defrosting a cooling element of a refrigerating systemcontaining a quantity of refrigerant which consists in, causing heatgenerated by an electrical heating element to be applied inside thewalls of the cooling element and directly to refrigerant containedtherein automatically in response to pressures of refrigerant within therefrigerating system.

. 7 A refrigerating system comprising in combination, a cooling element,a refrigerant circulating unit adapted to supply refrigerant to saidcooling element, means for controlling the operations of saidcirculating unit, an electrical heating element located within the wallsof said cooling element and arranged to apply heat generated therebydirectly to refrigerant within the cooling element for defrosting saidcooling element, and

said means being actuated automatically in response to conditions of.said system and being constructed and arranged to simultaneously rendersaid circulating unit inoperative and said heating element effective.

8. A refrigerating apparatus comprising, a cooling element having arefrigerating medium therein for maintaining same at a sufiiciently lowtemperature to cause frost to accumulate on the outer walls thereof, anda heating device within the walls of said cooling element for impartingheat to the refrigerating medium in said element to cause melting offrost from the walls thereof by flow of heat from the interior to theexterior of the element.

9. A refrigerating apparatus comprising, a cool- 5 ing element having arefrigerating medium therein for maintaining same at a sufliciently lowtemperature to cause frost to accumulate on the outer walls thereof, anormally ineffective electric heater within the walls of said coolingelement,

and automatically actuated means for rendering said electric heatereffective to cause heat to be imparted to the refrigerating medium insaid element whereby frost accumulated on walls thereof is melted by theflow of heat from the interior to the exterior of said cooling element.

- HERMAN J. DICK.

